A bearing is required to have an excellent rolling contact fatigue life, and various studies have been hitherto made on the improvement of rolling contact fatigue life. An example of the bearing member includes a bearing for use as an alternator of an automobile. It has already been known that one of the major contributors to causing the rolling contact fatigue fracture in a bearing is microstructural change called white structure generated right on the rolling contact portion of the bearing, which results in a crack generated and extended in the bearing to cause fatigue fracture.
Here, the aforementioned white structure is categorized into the following three types:                (1) white structure (hereinafter, also referred to as WEA), which is randomly generated without having any specific orientation relationship relative to the rolling contact portion;        (2) white structure (similarly referred to as butterfly), which is generated on the periphery of a non-metal inclusion in a direction at 45°; and        (3) white structure (similarly referred to as white band), which has orientations of about 80° and about 30° relative to the rolling contact portion.        
In particular, the generation of WEA leads to a bearing fatigue fracture in a shorter time before reaching expected rating life of the bearing, and thus countermeasures against WEA are in strong demand.
The WEA is considered to be generated, as described in Patent Literature 1 (PTL 1), through the following mechanism. That is, a lubricant oil used in the bearing or a water penetrating into the bearing is decomposed through a tribochemical reaction to generate hydrogen, and the hydrogen thus generated penetrates into the steel and is accumulated therein so as to accelerate the generation of WEA.
As examples of measures to be taken to suppress the generation of WEA, Patent Literature 2 (PTL 2) proposes a method of increasing Cr content and N content to thereby increase the amount of retained austenite, and Patent Literature 3 (PTL 3) proposes a method of adding Ni alone or simultaneously adding Ni and Mo together.